Recent clinical studies have shown that temperature perturbation either as hypothermia or hyperthermia has a profound effect on brain injury and recovery after cardiac arrest. While the temperature manipulation, either by hypothermia or fever reduction to prevent hyperthermia is widespread in clinical practice, the precise effect of temperature on brain injury is not fully known. Indeed, no methods to directly titrate the efficacy of hypothermia treatment, such as the time to initiate therapy, more optimal range or duration, are available. Effect of temperature manipulation on cortical function is not known either. In our preliminary studies we have observed that the neuroelectrical response, as reflected in the real time neuronal firing and the cortical neural activity, namely electroencephalogram (EEG), is directly affected by temperature. Together these two measurements can provide a real-time assessment of these brain responses from a limited yet specific area (spikes) to bulk or global areas of the brain (EEG). The two aims of this project are (1) to study the neuro- electrical response by quantitative EEG (QEEG) methods serving as a real time, non-invasive, electrical marker of the brain's response to temperature manipulation, and (2) to evaluate the interaction of the subcortical (spike activity) and cortical QEEG responses of the brain to temperature manipulation. Proof of concept obtained through this project will first of all lead to a clinically relevant tool to noninvasively monitor and titrate hypothermic neuroprotection following cardiac arrest. In addition, this feasibility study will open the door to more fundamental research on effects of hypothermia or hyperthermia at neuronal level as well as clinical investigations designed to optimize the therapy in humans. [unreadable] [unreadable]